JOURNAL OF BEIJING INSTITUTE OF TECHNOLOGY

Modeling Nonstationary Time Series for Gyroscopic Drift Analysing

Yang Weiqin, Jiang Hong

1995, 4(1): 1-6.

[Abstract](179)

Abstract:
A state space aproach for modeling nonstationary time series is employed in analysing gyro transient process. Based on the concept of smoothness priors constraint, the overall model is using the Kalman filter and Akaike's AIC criterion.Some numerical results of gyro drift models are obtained for analysis of gyro system. As the trend and irregular components of the observed time series can be modeled simultaneously, it is statistically more accurate and efficient than that modeled separately.

A New Hybrid Method for Constrained Global Optimization

Yang Ruoli, Wu Cangpu

1995, 4(1): 7-16.

[Abstract](253)

Abstract:
By combining properly the simulated annealing algorithm and the nonlinear programming neural network, a new hybrid method for comtrained global optimization is proposed in this paper. To maintain the applicability of the simulated annealing algorithm used in the hybrid method as general as possible, the nonlinear programming neural network is employed at each iteration to find only a feasible solution to the original constrained problem rather than a local optimal solution. Such a feasible solution is obtained by solving an auxiliary optimization problem with a new objective function. The computational results for two numerical examples indicate that the proposed hybrid method for constrained global optimization is not only highly reliable but also much more effcient than the simulated annealing algorithm using the penalty function method to deal with the constraints.

Application of Large-Scale Systems Theory in Fire Control Systems

Shi Tianyun, He Guangcun

1995, 4(1): 17-21.

[Abstract](190)

Abstract:
According the to the model of single tank fire control system, this paper makes use of decomposition-coordination theory of large-scale systems to discuss the shooting problem of multiple tank the control systems, and alalyzes specifically the three-tank the control systems and models.the process was imitated in computer, and the optimal shooting element of 3TS system was got. In addition, probability of hitting the target was calculated.

A Maneuvering Target Tracking Filter in Mixed Coordinate System

Dai Yaping, Yang Weiqin

1995, 4(1): 22-28.

[Abstract](196)

Abstract:
A kalman filter in the spherical-rectangular coordinate system to track a maneuvering target is introduced. A dynamic model with extended state vector is proposed in this paper to improve the state estimation (i.e. position, velocity and acceleration) even the sensor data(i.e. range, azimuth angle and elevation angle ) is color contaminated. The Kalman filter equations are decoupled by proper coordinate transformation and using filter gain rotation algorithm. Monto Carlo simulation is performed for different kinds of target trajectories(with the same measurement noise) and the root mean square values of estimation errors are computed. Results show that there is significant improvement in tracking capability over the methods discussed by other researchers.

An Effective Multiple Model Least Squares Method in Tracking of a Maneuvering Target

Yang Weiqin, Jia Zhaohui

1995, 4(1): 29-34.

[Abstract](272)

Abstract:
A polynomial model, time origin shifting model(TOSM, is used to describe the trajectory of a moving target .Based on TOSM, a recursive laeast squares(RLS) algorithm with varied forgetting factor is derived for tracking of a non-maneuvering target. In order to apply this algorithm to maneuvering targets tracking ,a tracking signal is performed on-line to determine what kind of TOSm will be in effect to track a target with different dynamics. An effective multiple model least squares filtering and forecasting method dadpted to real tracking of a maneuvering target is formulated. The algorithm is computationally more effcient than Kalman filter and the percentage improvement from simulations show both of them are considerably alike to some extent.

Exponential Stability of Large-Scale Non-Linear Systems with Multiple The Delays

Xie Sanming, Wu Yejun, Wu Cangpu

1995, 4(1): 36-41.

[Abstract](170)

Abstract:
The problem of stabilizing a class of large-scale non-linear multiple delay systems is considered.The complicated system is decomposed into several subsystems; each function of them is expressed by a set of components of the overall state vector,with interconnections between them, and the subsystems are coupled by the delayed state. In this paper, a method is devised to be a suitable choice of state feedback controls of every subsystems, moreover, it is proved that the large-scale system is exponential stable.

The Application and Design of the Economical Nonlinear Controller

Chen Jie, Gong Zhihao, Chen Lushen, Zhou Ning

1995, 4(1): 42-47.

[Abstract](186)

Abstract:
This anticle gives a design method of the economical nonlinear controller. The controller is composed of an expert intelligent coordination controller, a fuzzy prediction controller, a fuzzy feedforward controller, a nonlinear controller and so on. The consistence of a distributed control system based on this controller is also shown briefly.

Microcomputer Controlled High Precision Image Scanning Systems for Railway Tunnel Width Measurement

He Guangcun, Yang Weiqin

1995, 4(1): 48-52.

[Abstract](175)

Abstract:
There should be high resolution demand that is better than 1000 DPI(dot per inch) for high precision image scanning system. This paper introduced the two-level computer controlled system that consisted of LS-3500 film scanner, AST386/33 monitoring control level and Intel 8031 single chip computer that is used as DDC level. The formula for scanning image data processing and methods of statistic parameters calculating are described.

Improvement of Dynamic and Steady Characteristics of Pneumatic Position Servo with Fuzzy-PI Control

Yang Gongjun, Zhao Tong

1995, 4(1): 53-57.

[Abstract](172)

Abstract:
This paper provided a fuzzy-PI control. It makes use of the advantages of fuzzy controller for dynamic characteristics, and the advantages of PI control for steady characteristics of pneumatic position servo. Experimental results show that positioning accuracy meets the conventional industrial needs, and prove that the fuzzy-PI controller to be correct and more effective than the usual PID controller. The control method improve the dynamic and steady characteristics of the system.

An Expert System in Automatic Gauge Control for Rolling Process

Zhi Qiumei, Liang Qihong, Hou Chaozhen

1995, 4(1): 58-65.

[Abstract](198)

Abstract:
Beacuse the practical mathematic model of rolling process can't be built accurately,this paper established an expert system to control the rolling steels' gauge by adjusting the setup roll open, which combined the experience of theoreticians and operators. The system applied the expression method of rule-skeleton+rule-body', and selected an appropriate non-exact reference model and self-study algorithm. The whole system, including auxiliary routes, is designed in Borland C++. Some experiments on this system have been done, and a good result has been achieved.

Application of Fuzzy Modification Strategy in MRAC

Wang Liyan, Jin Zhili, Cao Fan

1995, 4(1): 67-72.

[Abstract](216)

Abstract:
Based on a simplified model reference adaptive control(SMRAC) algorithm a parameter modification algorithm according to fuzzy laws is proposed in this paper. The method makes the adaptive parameters in SMRAC only rely on the status of performance error. Thus it eliminates the influences of gain coefficients in SMRAC and the amplitude of input signal on the dynamic characteristics. Experiments on various step amplitudes and loads show that the performances of SMRAC are improved by incorporating fuzzy modification method.

Hierarchical Algorithms of Large-Scale Systems with Nonseparable Multiobjective

Xie Sanming, Wu Cangpu

1995, 4(1): 73-79.

[Abstract](167)

Abstract:
A class of large-scale hierarchical control systems is considered, the overall objective function is a nonlinear and nonseparable function of multiple quadratic performance indices.The separation strategy of the multiobjective optimization technique and the three-level objective coordination method are applied to the large -sacle systems, and a four-level hierarchical algorithms of optimization control is obtained.

The Algorithms of Adaptive Active Noise Control Systems in a Duct

Han Xiuling, Cheng Fan, Gao Jianlin, Li Chuanguang

1995, 4(1): 80-85.

[Abstract](206)

Abstract:
On the basis of the theory of adaptive active noise control(AANC) in a duct, this article discusses the algorithms of the adaptive control, compares the algorithm characteristics using LMS, RLS and LSL algorithms in the adaptive filter in the AANC system, derives the recursive formulas of LMS algorithm. and obtains the LMS algorithm in computer simulation using FIR and IIR filters in AANC system. By means of simulation, we compare the attenuation levels with various input signals in AANC system and discuss the effects of step factor, order of filters and sound delay on the algorithm's convergence rate and attenuation level.We also discuss the attenuation levels with sound feedback using are and IIR filters in AANC system.

Automatic Fast-North-Seeking Systems for Land Vehicle Nevigator

Xie Ling, Cui Yan, Si Kao, Chen Fengyu

1995, 4(1): 86-91.

[Abstract](172)

Abstract:
This paper summarizes the design result of automatic fast-north-seeking system for land vehicle navigator, dealing with principle of system combination hardware and software, as well as error analysis.

On the Azimuth Error of ESG Strapdown North-Seeking Instrument

Chen Jiabin, Lu Kai

1995, 4(1): 92-97.

[Abstract](185)

Abstract:
Because the vector of angular momentum of ESG (electrostatically suspended gyroscope) maintains the fixed direction in inertial space, it may be regarded as a fixed star. The astronavigation aigorithm is used to estimate the azimuth angle and the gyro constant drift in the paper. The relative errors which affect the estimation accuracy of the azimuth angle are the analysed.

1995 Vol. 4, No. 1